In 2002, a mysterious ancient bridge in the Palk Strait between India and Sri Lanka was revealed by NASA satellite photographs. The recently discovered bridge named as Adam's Bridge also known as Rama's Bridge or Rama Setu (Ram Setu) is made of chain of shoals, c.18 mi (30 km) long. The bridge's unique curvature and composition by age reveals that it is man made. Hindu belief is that the bridge was created by Shri Rama and Shri Lakshman with the assistance of Lord Hanuman and the vanara (ape men) army to reach Lanka in order to find Shri Rama's wife Sita who was kidnapped by Ravana and taken to his kingdom in Lanka. The legends as well as Archeological studies reveal that the first signs of human inhabitants in Sri Lanka date back to the a primitive age, about 1,750,000 years ago and the bridge's age is also almost equivalent.
Adam's Bridge (Aerial view)
A 2007 publication of the National Remote Sensing Agency said that the structure "may be man-made", contradicting the report from the Archaeological Survey of India which found no evidence for it being man-made. It says the satellite images have revealed an "ancient bridge between India and Sri Lanka in Palk strait".
"The origin of the bridge is a mystery. Archaeological studies have revealed that the bridge dates back to the primitive age, that is about 1,750,000 years."
"Its structure suggests that it may be man-made," it says on page 39 of the coffee table book under the sub-title 'Stunning Structures'.
"This 30 km long bridge, named as Adam's bridge, is made of a chain of shoals and links Rameshwaram in the south India to Sri Lanka."
Vanara building bridge to Sri Lanka
It goes on to say: "This has an echo in the ancient Indian mythological epic, the Ramayana. According to the epic, such a bridge was built by Lord Rama and his followers to reach Sri Lanka. Studies are still on but the bridge is seen as an example of ancient history linked to the Indian mythology."
The revelations in the book, with a foreword by Indian Space Research Organisation (ISRO) chairman G. Madhavan Nair, are in contrast to what the government has been maintaining so far that the setu is formed by giant tombolos - bars of sand connecting an island with another island of the mainland.
Geological Survey of India (GSI) carried out a special programme called "Project Rameswaram" that concluded that age data of corals indicate that the Rameswaram island has evolved since 125,000 years ago. Radiocarbon dating of samples in this study suggests that the domain between Rameswaram and Talaimannar may have thus been exposed around 18,000 years ago. Thermoluminescence dating by GSI concludes that the sand dunes of Dhanushkodi to Adam's bridge started forming only about 500–600 years ago. Investigation by Centre for Remote Sensing (CRS) of Bharathidasan University, Tiruchi, led by Professor S.M. Ramasamy dates the structure to 3,500 years.